我正在尝试从Windows虚拟文件夹(例如相机或iPhone图片文件夹)加载文件内容。以下是我用来测试的一些示例代码:
procedure TfrmForm.ButtonClick(Sender: TObject);
Var
Dialog: TAttachDialog;
Enum: IEnumShellItems;
Name: LPWSTR;
Item: IShellItem;
Strm: IStream;
OStrm: TOLEStream;
FStrm: TFileStream;
Result: HRESULT;
Buf: Array[0..99] Of Char;
Read: LongInt;
begin
Result := CoInitializeEx(Nil, COINIT_APARTMENTTHREADED Or
COINIT_DISABLE_OLE1DDE);
If Succeeded(Result) Then
Begin
Dialog := TAttachDialog.Create(Self);
Try
Dialog.Options := [fdoAllowMultiSelect, fdoPathMustExist,
fdoFileMustExist];
Dialog.Title := 'Select Attachments';
If Dialog.Execute(Self.Handle) Then
Begin
If FAILED(Dialog.ShellItems.EnumItems(Enum)) Then
Raise Exception.Create('Could not get the list of files selected.');
While Enum.Next(1, Item, Nil) = S_OK Do
Begin
If (Item.GetDisplayName(SIGDN_NORMALDISPLAY, Name) = S_OK) Then
Begin
mResults.Lines.Add(Name);
CoTaskMemFree(Name);
End;
If Item.BindToHandler(Nil, BHID_Stream, IID_IStream, Strm) = S_OK Then
Begin
OStrm := TOLEStream.Create(Strm);
FStrm := TFileStream.Create('C:\Temp\Test.jpg', fmCreate);
FStrm.CopyFrom(OStrm, OStrm.Size);
FreeAndNil(OStrm);
FreeAndNil(FStrm);
Strm := Nil;
End;
Item := Nil;
End;
End;
Finally
FreeAndNil(Dialog);
End;
CoUninitialize;
End;
end;
TAttachDialog是TCustomFileOpenDialog的后代,它公开了ShellItems属性。在我的实际应用程序中,我需要返回一个TStream对象。因此,在这个例子中,我使用TFileStream来复制源文件,以证明我已成功使用Delphi流访问文件。一切都正常工作,直到我尝试FStrm.CopyFrom时,此时我会收到一个“未实现”的错误。我做错了什么或者有没有更好的方法来完成我想要的功能?